1. Field of the Invention
The present invention relates to a control system of a continuously variable transmission for a vehicle and, more particularly, to engine braking control.
2. Description of the Prior Art
In a continuously variable transmission for a vehicle to continuously vary and transmit the revolutions of an engine to the wheels, there is known a control system for controlling the speed of a running vehicle by employing engine braking to adjust the speed ratio of the input shaft and output shaft of the continuously variable transmission, as disclosed for example, in Japanese Patent Laid-Open No. 59-219557. In this known control system, the target speed of the engine while braking, is stored so that the speed ratio of the continuously variable transmission may be adjusted to equalize the target speed and the actual speed of the vehicle during engine braking.
In the conventional control system of a continuously variable transmission for a vehicle, however, the transmission initiates the engine braking mode if the throttle opening is lower than a preset value and if the vehicle speed is higher than a preset value. This makes it difficult to enter the engine braking mode after the vehicle coasts down a long hill in that deceleration cannot be established as demanded by the driver.